1. Field of the Invention
An exemplary embodiment of the present invention relates to an attaching device and a method of fabricating an organic light emitting device using the same.
2. Discussion of the Related Art
Out of flat panel display devices, light emitting devices are a self-emissive type device that emits light by electrically exciting a compound. Since the light emitting devices do not need a backlight unit which is used in a liquid crystal display (LCD), the light emitting devices can be fabricated to be thin and light through a simple fabrication process. Furthermore, the light emitting devices can be fabricated at low temperature environment, and have characteristics of fast response time, low power consumption, excellent viewing angle, and high contrast.
In Particular, an organic light emitting device comprises an organic light-emitting layer between an anode electrode and a cathode electrode. The organic light emitting device forms an exciton, which is a hole-electron pair, by combining holes received from the anode electrode and electrons received from the cathode electrode inside the organic light-emitting layer, and emits light by energy generated when the exciton returns to a ground level.
In general, the organic light emitting device is fabricated by forming thin film transistors on a substrate, forming organic light emitting diodes on the thin film transistors to be electrically connected to the thin film transistors, and attaching the substrate to an encapsulation substrate. When the light emitting diode is bad although the thin film transistors are good, the organic light emitting device is determined as a defective good. In other words, process time and fabrication cost of the organic light emitting device may be wasted because the yield of the organic light emitting device is determined by the yield of an organic light emitting diode.
In order to overcome such a problem, an organic light emitting device was fabricated through the following processes. That is, a thin film transistor (TFT) array substrate provided with thin film transistors and an organic light emitting diode (OLED) array substrate provided with organic light emitting diodes were fabricated separately. A physical pressure was then applied to the TFT and OLED array substrates inside a process chamber to attach the TFT array substrate to the OLED array substrate.
However, it is difficult to uniformly maintain flatness between substrate supporters supporting the two substrates inside the process chamber when attaching the two substrates. It is also difficult to closely attach the entire surfaces of the substrates to the substrate supporters. Such difficulties reduce the process yield and increase fabrication cost of the organic light emitting device.
With a recent trend toward large-sized organic light emitting devices, the organic light emitting devices may be damaged because a pressure is applied to a portion of two substrates when attaching the two substrates. Therefore, life span and reliability of the organic light emitting devices are reduced.